This invention relates generally to a hypodermic needle that is useful for applying a local anesthetic to block nerve transmission, otherwise known as regional anesthesia.
Conventional hypodermic needles have a blade-like tip for penetrating the flesh, the tip having the orifice through which anesthetic or other liquid is ejected. It has been found that trauma to nerve fascicles results due to the slicing action of the conventional needle tip which literally cuts into the nerves themselves. Any direct intraneural injection resulting from cutting into the nerve and the tremendous fluid pressure through the orifice can result in post block nerve injuries. A study of causes of post anesthetic nerve damage (nerve palsy) suggests three major problems: (1) Direct damage to the nerve by the cutting edge of a conventional needle; (2) Neural trauma by high pressure intraneural injection of a local anesthetic resulting from the cutting and the position of the needle orifice, and (3) the toxic effect of the anesthetic or its perservatives from being subjected directly onto the interior of the nerve.
The present invention overcomes or minimizes the first two possibilities. This is accomplished by utilization of an improved needle tip which does not pierce or slice into the nerve fascicle nor permit an intraneural injection but instead allows for injection in the perineural space between the nerve fascicles.